Most, if not all Catholic colleges place an emphasis on service and volunteering. However, that does not necessarily translate to Catholic college requiring community service or volunteering. The expectations change from school to school.
Some Catholic colleges may require a certain amount of community service or volunteering hours in order for students to graduate. Sometimes this can mean having a certain number of hours per year or semester, or sometimes it may just be a total over the years in attendance.
Other Catholic colleges may not require community service or volunteering of their students, but they do encourage it. In either case, opportunities for service and volunteering are often readily available to students at any Catholic college. Many Catholic colleges, whether it's required or not, will have classes that involve service learning. In these cases, community service opportunities are built into the structure of the class, so that students can serve in some aspect while participating in the class.
Many Catholic colleges also have clubs that are dedicated to community service or volunteering where students can find plenty of opportunities for community service if they so desire. Additionally, through campus ministries, students may also be able to find opportunities for service through ministry or even mission trips.
While service is a core value of the Catholic faith, not all Catholic colleges will require it of students. To find out what sort of community service or volunteering is expected at a Catholic college, talk to an admissions officer or search the website of the college(s) you are interested in.